Air filter



FIG. 1 is a front elevation view of the design according to an embodiment of the invention.

FIG. 2 is a back elevation view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a bottom plan view thereof;

FIG. 5 is a right side elevation view thereof;

FIG. 6 is a left side elevation view thereof;

FIG. 7 is a front, right, and top perspective view thereof;

FIG. 8 is a front, left, and top perspective view thereof;

FIG. 9 is a back, right, and bottom perspective view thereof;

FIG. 10 is a back, left, and bottom perspective view thereof;

FIG. 11 is an enlarged, partial view of the front, right, and top perspective view of FIG. 7.

FIG. 12 is an enlarged, partial view of the front, left, and top perspective view of FIG. 8.

FIG. 13 is a cross-section of the design taken along line 13—13 as shown in FIG. 1; and,

FIG. 14 is a cross-section of the design taken along line 14—14 as shown in FIG. 1.

The elements shown in broken lines are for illustrative purposes only and form no part of the claimed design. 

The ornamental design for an air filter, as shown and described. 